Reverse-Thread Nut Locking Assembly for Vibration Resistance
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Solution Overview
Problem
Existing locking devices with reverse-direction threads face difficulties in assembly and locking due to limited angle of rotation, making them difficult to mount and dismantle, and are prone to unscrewing under vibrations.
Innovation Solution
The locking device features identical and constant thread pitches for all threads and tappings, with increased radial clearances and standardized ISO triangular profiles, allowing for a wider range of rotation and incorporating a visual marking system and positive locking mechanism with a washer for secure engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If different pitches are used between the thread of the assembly 'ring/nut' and the threads of the 'screw/nut' and 'screw/ring' assemblies, then the ring can rotate relative to the nut over a fairly wide angle, but the assembly becomes difficult to mount and lock
Solution Approach 1:
The patent applies different radial clearances to different thread interfaces: the first radial clearance (screw/nut) and third radial clearance (ring/screw) are smaller, while the second radial clearance (nut/ring) is larger. This local differentiation allows the ring to rotate sufficiently relative to the nut for assembly and disassembly, while maintaining proper locking characteristics at the screw interfaces.
2Reliability
If the thread flanks are in contact to maintain tightened elements, then the locking is secure, but the device is prone to unscrewing under vibrations
Solution Approach 1:
The patent employs reverse-direction threads: the first thread on the screw has a right-hand pitch while the second thread on the ring has a left-hand pitch. This inversion creates opposing wedge forces on the nut that push it against the screw head, maintaining constant contact and preventing vibration-induced loosening through self-locking mechanics.
Data Source
AI summary
The present invention relates to a unit (10) for a locking device, including: a nut (12) comprising first (18) and second (20) coaxial taps in opposite directions; and a ring (13); said ring including a third tap (38); the first (18) and third (38) taps being capable of engaging with a single first thread (22); said ring including a second thread (40) capable of engaging with the second tap (20) of the nut. A portion (33) of the ring, projecting relative to the second thread (40), includes a through-hole (60); and a surface (16) of the nut includes a visual marking, configured to be opposite the hole (60) when the nut and the ring are in an installation position, and separated from said hole when the nut and the ring are outside said installation position.